1. Field
The present disclosure relates generally to the manufacturing of structures and, in particular, to the manufacturing of aircraft structures. Still more particularly, the present disclosure relates to a method and apparatus for maintaining a selected configuration of a structure during the manufacturing of a completed aircraft structure using the structure.
2. Background
As one example, the front spar assembly and the rear spar assembly for a wing may need to be held in certain positions relative to each other, while various operations are performed to assemble the wing. These operations may be performed simultaneously, at different times, or both. The operations performed may include, for example, without limitation, any combination of drilling, countersinking, fastening, coupling, sealing, coating, inspecting, painting, welding, machining, bonding, additive manufacturing processes, or other suitable types of operations.
Some currently available methods for assembling an aircraft structure use rigid fixtures to hold components in certain positions during the assembly process. In some cases, these rigid fixtures may be fastened to the factory floor to form an assembly line for manufacturing the aircraft structure. However, these fixtures may limit future expansion of the assembly line because the fixtures are typically permanently fastened to the factory floor. For example, these rigid fixtures may take the form of fixed monuments that are bolted to the factory floor or secured to the factory floor in some other manner.
Further, these fixtures may be unable to accommodate the manufacturing of aircraft structures of different shapes and sizes. Once installed, the rigid fixtures may not allow the flexibility needed to account for aircraft design changes, changes in manufacturing locations, changes in aircraft production rate, or other types of changes. Consequently, using these types of rigid fixtures for the assembly of aircraft structures may cause the assembly process to be more time-consuming and expensive than desired. Additionally, the rigid fixtures may require more maintenance than desired over time.
For example, one manner in which an aircraft structure, such as a wing, may be currently held in a horizontal position may involve the use of fixed supports such as a fixed jig. This type of assembly of a wing may be referred to as a horizontal build. A fixed jig may be a structure or device that may be used to hold the parts for a wing.
The fixed jig may be attached to the floor of the manufacturing environment and may not move or be moved from one floor location to another floor location. In other words, the fixed jig may be immobile. The fixed jig may have tools that may be attached to the parts for the wing at control points. These tools may hold the parts at the control points to restrain assembly dimensional shape within tolerances and the parts in the desired position for assembly of the wing. Control points may be attachment points on the structure such as leading or trailing edge attachment points or control surface hinge points for structures such as slats, spoilers, rudders, flaps, control surfaces, or other points where something can be attached to the structure during the build process.
The tools in the fixed jig may have a feedback loop, may have support to the floor, and may be calibrated with respect to global positions. These types of fixed jigs may be expensive, immobile, inflexible, and may cause bottlenecks in manufacturing. A system of discrete pogos may be used to hold parts for assembly into a wing. As the number of control points increases, this type of system may become cluttered and advantages of this type of system may be reduced. Further, pogos may be numerically controlled and may require considerable capital investment.
With the currently used systems for holding parts for the assembly into wings, a large number of control points are used to ensure that the wing may be assembled with a correct orientation, location, and acceptable deflection. Managing these control points with a horizontal build for a wing may result in less than desirable manufacturing conditions. For example, with the large number of control points, access to the spars, wing edge, and the bottom side of the assembly for the wing may be more difficult than desired. Therefore, it would be desirable to have a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues.